Patient RB

Case RB: KeraSoft^® IC SMC (Sector Management Control)

RB had just qualified as a commercial jet pilot in 2006 when he was diagnosed with Keratoconus. This immediately disqualified him from flying unless he could find a reliable contact lens option. He tried various keratoconic contact lens design options and found a reasonable result with RGP lenses. Although he just about attained the required visual standard for flying with these when in place, he took the decision not to fly because the RGPs easily displaced off the cornea, did not centre well especially on the left eye and hence reduced his consistent vision.

RB had Collagen Cross Linking (CXL) treatment on both eyes in September 2007. Following the treatment, his ophthalmologist did not want him to suffer any possible moulding effects from RGP lenses.

He was now also working within other areas of the aviation industry, commuting between Canada (winter) and Kuwait and needed lenses that could withstand the resultant extremes in temperature.

RB was also desperate to get his flying licence back, so he could continue with his chosen career.

Initial Clinical measurements:

Spectacle RX:	R: 3/60 -4.50/-3.00 x 80 VA 6/9	L: 6/60 -2.50/-3.00 x 80 VA 6/36
RGP lenses:	R: 7.20/8.70/-6.25 VA 6/7.5	L: 6.80/8.70/-6.50 VA 6/9+2
Keratometry:	R: 7.35 X 20/7.14 X 110	L: 6.85 X 134/6.42 x 44

 

Topography (Absolute measurement):

RB was fitted with KeraSoft^® contact lenses

In this case, fitting normal KeraSoft^®3 design attained the same acuity as the RGP lenses in the left eye, where the lenses tended to decentre off temporally. There was also ghosting present from residual Higher Order Aberrations (HOAs) which RB found to be unacceptable for flying.

He was therefore refitted in KeraSoft^®IC SMC design, which allows individual customisation of two separate peripheral curves at any location in the peripheral zone to allow alignment of to the steepest and flattest areas of the irregular cornea.

KeraSoft^® IC lens technical details

 

In RB’s case, a standard periphery was chosen for the superior portion of the lens and a Steep 3 for the inferior.A 15.00 diameter lens was chosen to increase stability.

The result was a comfortable, stable lens in both eyes, with which RB was able to achieve 6/4- with both eyes. The final KeraSoft^®IC lenses and acuity achieved are shown below.

 

 

 

 

R: 8.60/15.00/STD superior periphery/Steep 3 inferior/-5.00/-1.25 x 45 VA 6/4-3
L: 8.60/15.00/STD superior periphery/Steep 3 inferior/-5.00/-3.75 x 147 VA 6/4-2

 

Topography with lenses in situ.

Discussion

All conventional lenses had failed to provide acceptable acuity or reduce the considerable ghosting caused by coma aberration. Using the KeraSoft^®IC SMC design gave better centration and reduced coma aberration by approximately 50%. Although there was some slight residual ghosting from the left eye, this was easily suppressed binocularly.

RB attained 15 hours plus wearing time and found the lenses equally comfortable in the depth of a Canadian winter as well as the height of a Kuwaiti summer (50°C). The stability of the lenses and the acuity achieved has now enabled him to go back to being a commercial pilot – he is delighted with this result.

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